Final answer:
Inspiratory capacity is calculated by adding tidal volume, the air inhaled or exhaled during normal breathing, to inspiratory reserve volume, which is the additional air inhaled with effort after a normal breath.
Step-by-step explanation:
Inspiratory capacity (IC) is a pulmonary volume that is used to assess the amount of air a person can inhale after a normal exhalation. It is the sum of two respiratory volumes: the tidal volume (TV) and the inspiratory reserve volume (IRV). Tidal volume is the amount of air inhaled or exhaled during normal breathing, while inspiratory reserve volume is the additional amount of air that can be inhaled with effort after a normal inhalation. Therefore, the correct answer to the question is 'Inspiratory capacity is the sum of tidal volume and inspiratory reserve volume'.